In the related art, as disclosed in Patent Document 1, an optical fiber unit formed by winding binding materials on a plurality of optical fiber cores or optical fiber strands (hereinafter, simply referred to as optical fibers). In the optical fiber unit, binding materials are wound, so it is possible to prevent the bundle of optical fibers from becoming loose, and it is also possible to improve the discrimination among the plurality of optical fiber units depending on the colors of binding materials.
In addition, Patent Document 2 proposes an optical fiber unit in which a plurality of binding materials are wound in an SZ shape on a bundle of optical fibers, and two binding materials are adhered to each other at reversed portions in the winding direction. According to this configuration, when the part at which the two binding materials are adhered to each other is peeled off, the binding around the peeled part is released and the binding at the other part is maintained. Thus, it is possible to improve workability of intermediate post-branching or the like of the optical fiber unit.
[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2010-26196
[Patent Document 2] Japanese Unexamined Patent Application, First Publication No. 2012-88454
In the optical fiber unit described in Patent Document 2, since binding materials are adhered to each other at reversed portions, the adhesive part could be unexpectedly peeled off, so that the binding state tends to become unstable.